NEUROASSESSMENT CORE PROJECT SUMMARY/ABSTRACT: The newly reorganized, streamlined NeuroAssessment Core (NAC) will have the overall goal of supporting comprehensive neuromedical, neurobehavioral and neuroimaging assessments for the characterization of HIV+ individuals and HIV- controls in HNRC-affiliated studies. The Core will comprise 3 integrated subunits: Neuromedical (NM), Neurobehavioral (NBh) and Neuroimaging (NI). We aim to facilitate and enhance multidisciplinary research in neuroAIDS by providing a range of services, training and scientific consultation to projects such as investigator-driven R01s and R21s, international neuroAIDS studies, and a variety of intra- and extramural investigations. Historically the Core and its investigators have been leaders in the field, spurring the development of new methods and adapting to the continually evolving scientific landscape. Consistent with this, the Core will provide resources to support the Center's new themes of HIV persistence and cure, and how the human gut microbiome interacts with HIV and its treatment to affect the CNS. Specific services relevant to HIV persistence and cure include serial lumbar punctures to evaluate viral rebound following HIV reservoir interventions, and high volume CSF collection and neurocognitive (NC) testing to assess effects of such interventions on brain functioning. The gut microbiome will be characterized by collecting and processing samples of stool. Standard evaluations will continue to include a structured neuromedical history, clinical and laboratory examinations, and establishment of diagnoses of central and peripheral neurological complications of HIV. The NAC's NI Unit will provide resources, including training, consultation, and technical support, for the detection and measurement of HIV- related brain injury using a broad array of techniques, including structural, functional, and metabolite MRI and PET imaging. This work will support investigations of the cognitive consequences and neuromedical correlates of these effects; the underlying pathological mechanisms that give rise to this damage; and potential biomarkers for treatment success. The NBh Unit will perform a comprehensive assessment of all participants in the HNRC cohort that will include well-validated measures of NC functioning, psychiatric status, and everyday functioning, in accordance with the HAND diagnostic guidelines. The NBh Unit's specific Resource Objectives are to provide: 1) demographically-adjusted individual, domain, and global summary scores of NC functioning; 2) Determinations of NC change in individual participants using reliable and validated actuarial methods; 3) Self-assessment and laboratory-based measures of everyday functioning; 4) Current and lifetime history of mood and substance use diagnoses; and 5) Technical assistance, training, certification, consultation, and career development mentoring. Data generated by the NAC range from NC performance and diagnostic formulations to ART information, disease staging and viral loads (VLs), to clinical laboratory measurements, medical histories, and physical examinations.